Floating liquid intake

ABSTRACT

A floating liquid intake for a liquid suction removal system, the liquid intake comprising housing defining an internal cavity. The housing has a hollow and buoyant annular body, an upper cover and a lower cover. The internal cavity is formed between the upper and lower covers. A substantially annular inlet is formed in the annular body for ingress of liquid into the cavity. The annular body has a buoyancy sufficient for the liquid intake to float in a liquid with the annular inlet submerged below the surface of the liquid in which the liquid intake is floating. A pipe extends into the cavity and the pipe includes an inlet that in use is open below the surface of the liquid within the cavity. The pipe extends outside of the cavity for connection to a liquid suction removal system.

PRIORITY CROSS-REFERENCE

The present application is a continuation application of U.S. patentapplication Ser. No. 16/955,834, filed 19 Jun. 2020, which is a nationalstage application, filed under 35 U.S.C. § 371 of International PatentApplication No. PCT/AU2018/051394, filed 21 Dec. 2018, which claimspriority from Australian Provisional Patent Application No. 2017905172filed 22 Dec. 2017 the contents of which are to be considered to beincorporated into this specification by their reference.

TECHNICAL FIELD

The present invention relates to a floating liquid intake for a liquidsuction removal system. The present invention has been developed inrelation to the removal of water (“dewatering”) from settling ponds,tailing dams, decant ponds, raw water dams, rivers and waterways and itwill be convenient to describe the invention in relation to thoseapplications. However, it is to be appreciated that the invention is notlimited to those applications.

BACKGROUND OF INVENTION

The following discussion of the background to the invention is intendedto facilitate an understanding of the invention. However, it should beappreciated that the discussion is not an acknowledgement or admissionthat any aspect of the discussion was part of the common generalknowledge as at the priority date of the application.

Settling ponds, tailing dams and decant ponds are used in the miningindustry for separating solids or immiscible liquids from water. Pondsand dams of this kind are used in mining sites where the tailingsby-products of the mining processes that are entrained in water areseparated in the pond or dam. The inflow of tailings into a tailings damconstantly adds water to the dam and that water can be removed for reusein the mining operation. Liquid removal systems are thus used for thatpurpose. Likewise, the agriculture industry employs dams for holdingwater for irrigation or relies on rivers for watering stock and removalof that water from dams and rivers is required when the water is to beused.

One liquid removal system known to the applicant employs a suctionpumping system in which a pump inlet at the end of a pipe is positionedat or close to the floor of the settling pond or tailings dam so thatwater is pumped from the pond or dam from that position. A disadvantagewith this form of liquid removal system is that the proximity of thepump inlet to the floor of the pond or dam means that the solids thathave settled on the floor of the pond or dam are likely to be suckedinto the pump inlet if sufficient suction is applied by the pumpingsystem. A further disadvantage of this system is that the pump inlet ispositioned where the water is generally least clean and/or has thegreatest amount of suspended solids (being towards the floor of the pondor dam where suspended solids sink towards) and so invariably, tailingsmatter will be entrained in the water being removed. In either instance,there can be a detrimental effect for example on the equipment of thepumping system, i.e. clogging filters and pumps and reducing pumpingefficiency, while reuse of the water can be affected if it is too highlycontaminated with tailings matter.

Additionally, where the liquid removal system is employed to removesalty water, the higher concentration salty water gravitates to thefloor of the dam, leaving the lower concentration salty water at ortowards the surface of the dam, so that saltier water is removed usingthe system described above than could be the case if the pump inlet werepositioned towards the surface of the dam. This can cause obvious issuesif the water is being used for irrigation or stock feed.

The preference is thus for the pump inlet to be positioned furthest awayfrom the floor of the pond or dam and in the most clean water, so thatsubstantially only clean water is removed.

Another liquid removal system known to the applicant employs a floatwhich suspends the pump inlet at an upper level in the pond or dam. Thissystem is illustrated in FIG. 1 which shows a dam 10 having a floor 11,a body of silt and debris 12 resting on the floor 11 and a body of water13 above the silt and debris 12. There will often be a transition zonebetween the body of silt and debris 12 and the body of water 13 in whichsilt and debris is suspended in the water, whereby the density of thesuspension is greatest adjacent the body of silt and debris 12. Floats14 suspend a pipe 15 that extends to a pump inlet 16 at one end and apump 17 at the opposite end. The system of FIG. 1 advantageously atleast initially locates the pump inlet 16 away from the floor 11 of thepond or dam 10 and thus away from the silt and debris 12, howeverbecause of the proximity of the pipe inlet to the surface of the body ofwater 13, a strong suction from the pump can create a vortex in thewater which can allow air to enter the pump system through the pumpinlet 16. This can lead to significantly lower pumping performance byaffecting the volumetric performance of the pump 17, i.e. the volume ofliquid that can be displaced from the pond or dam 10 by the pump 17, butmore importantly, the existence of air in the liquid flow through thepump 17 can damage the pump 17 through vibration and there can be a lossof pump performance. The solution is to lower the pump inlet 16 to adepth at which vortices are not formed, which is under the level of whatis known as “critical submergence”, to prevent the formation ofvortices, so that air does not become entrained in the flow through thepump inlet 16. However, this requires that the pump inlet 16 be loweredto be closer to the floor 11 of the pond or dam 10 and that positioningraises the issue of the first approach discussed above in which in whichsediment and solids can be sucked into the pumping system through thepump inlet 16 if the pump inlet 16 is not at or towards the surface ofthe pond where the cleanest water is located.

There is thus a tension between placing the pump inlet at a positionwhere the cleanest water is located, i.e. towards the surface of thepond or dam, as compared to a position at which the generation ofvortices is avoided. This tension means that the pump inlet is oftenplaced at the deepest section of a pond or dam so that the pump inletcan be placed shallow enough to entrain relatively clean water, but alsodeep enough to prevent the generation of vortexes. This often means thata significant length of pipe must be used to position the pump inlet atthe deepest section of a pond or dam (usually the centre of the pond ordam) thus increasing line losses caused by friction between the waterand the pipe and thus reducing pump efficiency.

The point of critical submergence at which a pump inlet can bepositioned within a body of water in which vortices will be avoided isdependent on factors such as the size of the pump inlet and it's designgeometry, the volume of water being pumped (the pump inlet velocity) andthe depth of submersion of the pump inlet below the surface of thewater. The approaches described above work adequately in ponds or damsof sufficient depth that allow the pump inlet to be positioned in cleanwater, at a depth which is at or below the point of criticalsubmergence, but away from the sediment located on the floor of the pondor dam. However, ponds and dams are often shallow at the point at whichthe pump inlet can be positioned and shallow water presents a difficultyin relation to liquid removal given the needs expressed above to avoidingress of sediment and solids into the pump inlet and the need to avoidthe generation of vortices.

Another issue with systems in which a float is used to suspend the pumpinlet at an upper level in the pond or dam is that as the water levelreduces in the pond or dam, the suspended pump inlet moves closer to thefloor and thus to the sediment and solids that are present at the floor,increasing the likelihood of entraining the sediment and solids throughthe pump inlet into the pumping system over time. In these systems,because the suspended pump inlet is suspended at a depth which is at orbelow the point of critical submergence so the pump inlet is below theliquid surface of the pond or dam, the body of water above the pumpinlet is not a usable body in terms of positioning of the pump inlet inclean water and away from the floor of the pond or dam. The potentiallyclean body of water above the pump inlet can therefore not be accessed.

The applicant has already developed a floating liquid intake which isthe subject of International Patent Application PCT/AU2017/050697. Whilethe invention of that application provides advantages over the priorart, the applicant has developed the present invention to providefurther advantages as will become apparent from the followingdescription.

SUMMARY OF INVENTION

According to the present invention, there is provided a floating liquidintake for a liquid suction removal system, the liquid intake comprisinghousing defining an internal cavity, the housing having:

a hollow and buoyant annular body,

an upper cover extending upwardly from the annular body, and

a lower cover extending downwardly from the annular body,

the internal cavity being formed between the upper and lower covers,

a substantially annular inlet formed in the annular body for ingress ofliquid into the cavity,

the annular body having a buoyancy sufficient for the liquid intake tofloat in a liquid with the annular inlet submerged below the surface ofthe liquid in which the liquid intake is floating,

a pipe extending into the cavity, the pipe including an inlet that inuse is open below the surface of the liquid within the cavity, the pipeextending outside of the cavity for connection to a liquid suctionremoval system.

A floating liquid intake according to the present invention providesvarious benefits over the prior art which will become apparent from thediscussion that follows.

A floating liquid intake according to the present invention includes ahollow, annular and buoyant body, which can provide the sole form ofbuoyancy for the liquid intake. Moreover, the annular body can form aring from which the upper and lower covers extend and through which eachof the annular inlet and the outlet pipe opening extend. The annularbody is thus formed in a manner that means that the number of componentparts that the liquid intake requires is reduced, compared to the priorart and in particular the applicant's prior floating liquid intake whichis the subject of International Patent Application PCT/AU2017/050697.The formation of the annular body as a buoyant body has allowed theliquid intake to be developed in a manner that can be more easilycommercially manufactured, as the annular body can be manufactured as asingle part and the remaining components attached or assembled thereto.The reduction in component parts means the manufacturing time and effortto produce a liquid intake according to the present invention is reducedand the manner in which the annular body can be formed means that theaccuracy of manufacture is high and repeatable.

The liquid intake can be formed to depth in the vertical direction thatis much less than the width in the horizontal direction, so that theliquid intake is disc shaped. The annular body can have the greatestdiameter of the liquid intake in the horizontal plane so that all othercomponents of the liquid intake are inboard of the periphery of theannular body in the horizontal plane. This makes the liquid intake verystable when floating. The diameter of the annular body can be in theorder of 3 m, or greater or lesser.

The annular body has a buoyancy that is sufficient for the liquid intaketo float in a liquid with the annular inlet submerged below the surfaceof the liquid in which the liquid intake is floating. The annular inletis substantially horizontal when the liquid intake is floating, althoughof course movement in the liquid will cause movement of the annular bodyand thus the annular inlet. The annular inlet is also intended to have asubstantially uniform or constant inlet cross-section or shape so thatthe volume of flow of liquid through the inlet is constant about theinlet subject to a constant suction pressure being applied through thepipe inlet.

With the annular inlet submerged below the surface of the liquid inwhich the liquid intake is floating, the annular body can disrupt anyvortices that form through suction of liquid into the liquid intake orcan prevent the formation of vortices. This occurs because liquid isdrawn into the cavity about substantially the full circumference of theannular body rather than in principally a single direction or from asingle area, as is the case in prior art systems in which a pump inletis placed too close to the surface of a body of liquid. This isimportant as the approach velocity of liquid arriving at the pipe inletof a floating liquid intake according to the present invention will besubstantially uniform from all directions and is slower than for priorart intakes, so that the energy available to form and maintain a vortexis lower. Beneficially, this means that the likelihood of forming avortex is much lower than in prior art intakes and testing has shownthat an acceptable suction pressure can be employed in which vortexesare not formed. This suction pressure can be the same as, or even higherthan in prior art intakes, so there is no reduction in suction and thusthere is no reduction in suction performance by adopting the presentinvention.

A further benefit of the present invention is that debris, fish andother fauna are more likely to float past the pipe inlet than to beentrained into the inlet and subsequently be sucked into the pumpingsystem, given the relatively slow flow of liquid past or to the pipeinlet. Still further, the relatively slow flow of liquid past or to thepipe inlet reduces the propensity for the liquid flow to disturb thesediment and solids on the pond or dam floor, so that the sediment andsolids are not lifted into the water above them. Despite this, inletcovers, shields or screens can be employed over the annular inlet toresist ingress of debris and other matter into the cavity of the liquidintake if required, such as in particularly debris laden liquid, floodwaters for example.

As a broad rule, to achieve an approach velocity in which the abovedescribed benefits are provided, the radius of the annular inlet shouldbe at least about equal to the height of the critical submergence thatwould otherwise apply to a prior art liquid removal system. Thus, wherea critical submergence of 1.5 m would apply, the radius of the annularinlet should likewise be at least about 1.5 m. A greater radius can beprovided, but a lesser radius is preferably avoided.

Moreover, any vortex that is formed outside the periphery of the liquidintake is disrupted by the annular body which forms an impediment to theflow of the upper layer of liquid within which the liquid intake ispositioned.

Advantageously, this means that the liquid intake of the presentinvention can be used to extract water from close to the surface of adam or pond where the cleanest liquid is normally located and becausethe liquid intake floats on the surface of the dam or pond, the changinglevel of the dam or pond does not affect the position of the pipe inletrelative to the surface of the dam or pond. This allows the liquidintake of the present invention to be used in shallow liquid that wouldnot be appropriate for prior art liquid removal systems andbeneficially, this allows the liquid intake of the present invention tobe positioned closer to the edges of a dam for example rather than beingpositioned inboard of the edge in deeper regions of liquid.

Testing of a liquid intake according to the present invention has foundthat it is able to operate effectively in water depths as shallow as 400mm without creating vortexes that lead to loss of pump performance andpump damage within the pumping system. That depth is not suitable withother prior art liquid removal systems (although could be suitable forapplicant's prior floating liquid intake which is the subject ofInternational Patent Application PCT/AU2017/050697) except if thesuction pressure is significantly reduced. Testing has also shown thatin water depths as shallow as 400 mm, the cleanest water is still beingdrawn given that the pipe inlet can be placed only just below thesurface of the water within the cavity of the liquid intake.

The ability to operate in depths as shallow as 400 mm offers significantbenefits to the present invention. As indicated above, it means that theliquid intake according to the present invention can be placed closer tothe bank of a pond or dam than prior art arrangements and this leads togreater efficiency due to a reduction in line losses. For some ponds ordams with relatively steep embankments, the liquid intake of the presentinvention can be placed within stepping distance off the water's edge,such as within 0.5 m off the water's edge. This contrasts with someprior art arrangements as described above in which the pump inlet islocated a significant distance away from the water's edge and well belowthe water surface. Notably, the liquid intake of the present inventionwill not dredge or erode the bank of the pond or dam when it is placedclose to the bank as might occur with prior art arrangements, becausegenerally, the velocity of liquid generated by the liquid intake is lowand gentle. These are significant benefits realised by the presentinvention.

The annular body can be of significant size. While the liquid intake canhave different sizes for different applications, typical sizes of theliquid intake include a small version in which the annular body has anoutside diameter of about 1 m and a large version at an outside diameterof about 3 m. The annular body has thus been developed for rotationalmoulding which allows the annular body to be formed in one piece or partand accurately produced repeatedly. Rotational moulding also allows theannular body to be formed from suitable materials including mediumdensity polyethylene (MDPE). The use of rotational moulding forproducing the annular body has been a key development in the manufactureof the liquid intake of the present invention and is expected to allowmore automated production of the liquid intake in less time compared tothe floating liquid intake which is the subject of International PatentApplication PCT/AU2017/050697 and which has a more complex assembly anda greater number of parts. The floating liquid intake of InternationalPatent Application PCT/AU2017/050697 is fabricated and does not includean annular body that is hollow or that is rotationally moulded.Moreover, the buoyancy of the liquid intake of International PatentApplication PCT/AU2017/050697 is provided by a separate floating portionrather than the annular body from which the upper and lower coversextend. The annular body of the liquid intake of the present inventionthus provides advantages over the prior art including the liquid intakeof International Patent Application PCT/AU2017/050697.

The annular body is a buoyant body. The buoyancy should be sufficientfor the liquid intake to float in a liquid with the annular inletsubmerged below the surface of the liquid in which the liquid intake isfloating. In some forms of the invention, the annular body is buoyant onthe basis of the annular body being hollow. In these forms of theinvention, the annular body is preferably formed of a material that isresistant to puncture or tearing. Puncture or tearing of the annularbody can occur during installation of the liquid intake in a body ofliquid (a pond or dam for example) as installation can involve theliquid intake being pushed or dragged over a ground surface and into thebody of liquid. The ground surface can be the polyethylene lining on atailings dam, or the relatively soft surfaces near the edge of a dam orpond, or even across rocks surrounding the body of liquid. While theliquid intake might be supported on skids for travel to the body ofliquid, the annular body can nevertheless be exposed to contact withground surfaces that can puncture or tear the material of the annularbody unless the material is of sufficient wear resistance.

In other forms of the invention, the hollow inside of the annular bodyis filled with a buoyant material or substance such as polyurethane (PU)foam. By this arrangement if the annular body is punctured or torn, itwill remain buoyant by virtue of the internal buoyant filling. A furtheradvantage is that the filling of the annular body with a buoyantmaterial can increase the rigidity of the annular body and can provide,if required, a substrate into which fasteners can embed for theattachment of components to the annular body. The buoyant material canfor example, be injected into the annular body in any suitable manner.

The cavity of the liquid intake is formed between the upper and lowercovers. The annular body can form part of the cavity as a componentintermediate the upper and lower covers. The upper cover and/or thelower cover can be formed concavely to have a dome shape. Where each ofthe upper and lower covers is formed concavely to have a dome shape, thecavity can be generally symmetrical about a horizontal plane through theannular body, although the upper and lower covers can be differentlyshape domes so that cavity is generally asymmetrical about a horizontalplane through the annular body. In some forms of the invention, theupper cover has a greater diameter than the lower cover.

The annular body can have upper and lower surfaces and radially spacedinner and outer edges. The upper cover and lower cover can attach to andextend from the respective upper and lower surfaces. The annular bodycan have an opening through which the pipe extends. The opening canextend through the annular body from the outer edge to the inner edge.

The annular inlet formed in the annular body can separate the annularbody into first and second annular portions. These portions can extendin parallel planes that, where horizontal, are separated vertically toform the annular inlet. Thus, the first and second annular portions arespaced apart and the annular inlet is formed by the spacing between thefirst and second annular portions.

The annular body can still be rotationally moulded and both portions canbe hollow, although it is an option for the lower portion to be solid.The first and second annular portions can be connected by struts, websor bracing that again, can form part of the rotational moulding to formthe annular body. The struts, webs or bracing can be spaced apart toallow the passage of liquid therepast. The first and second annularportions can alternatively be connected by a substrate that isperforated or slotted to allow the passage of liquid through thesubstrate.

The first annular portion can be the upper of the two annular portionsand can have a greater outside diameter than the second and lowerannular portion. The outside diameter of the lower second annularportion can be radially inboard of the inside diameter of the upperfirst annular portion to create the annular inlet of the annular body.

Ribs or baffles can be used within the cavity of the liquid intake forthe purpose of arresting or inhibiting unwanted or undesirable liquidmovement within the cavity. This liquid movement can be swirlingmovement that can be generated by the suction through the pipe inlet.The ribs or baffles can interrupt that swirling movement, or can preventit from commencing. That swirling movement can generate air bubbleswhich can become entrained within the liquid entering the pipe intakeand so minimising the liquid movement is advantageous, noting that theremust be some movement within the cavity for the liquid to be removed viathe liquid intake. Acceptable movement is movement which isnon-turbulent and so other movement that generates turbulence ismovement that is to be resisted or eliminated if possible. The ribs orbaffles can be placed anywhere within the cavity and can extend fromanyone or more of the upper and lower covers and the annular body. Insome forms of the invention, baffles extend upwardly from the lowercover into the cavity. This is convenient as the lower cover will alwaysbe immersed in liquid when the liquid intake is operating.

By employing an annular body of a buoyancy in which in use of the liquidintake, the annular inlet is submerged below the surface of the liquidin which the liquid intake is floating, a vacuum can be formed withinthe cavity if the upper cover is airtight in connection with the annularbody, i.e. the annular inlet is substantially the only inlet into thecavity. It is the vacuum within the cavity that draws liquid into thecavity so liquid is drawn to the pipe from the side or radially, ratherthan from above the pipe inlet. This prevents vortexes from formingwithin the cavity and as explained earlier, vortices that would formoutside the liquid intake are eliminated from continuing to within thecavity by disruption by the annular body.

The development of a vacuum within the cavity can lead to the height ofthe liquid within the cavity being higher than the surface of the liquidsurrounding liquid intake. This can be important because a feature ofthe liquid intake of the invention is the ability to have the pipe inletface either upwards or downwards. By the generation of a vacuum, theliquid level within the liquid intake can be higher than the liquidsurrounding the liquid intake and this assists to ensure that liquidwill flow into the pipe inlet. This has the advantageous effect ofallowing the liquid intake of the invention to operate in waterspotentially even shallower than 400 mm with no loss of performance.

Suction pumps have a limitation in that they have a theoretical maximumlift of no more than about 10 m. This assumes a perfect vacuum and veryfew friction losses and in practice, the suction lift is less than thisand more likely to be in the order of about 8.5 m. While that level oflift is suitable for many applications, if a greater lift is required,than the present invention can employ a submersible pump within thecavity of the liquid intake. Thus, in accordance with another aspect ofthe present invention, there is provided a floating liquid intake for aliquid suction removal system, the liquid intake comprising housingdefining an internal cavity, the housing having:

a hollow and buoyant annular body,

an upper cover extending upwardly from the annular body, and

a lower cover extending downwardly from the annular body,

the internal cavity being formed between the upper and lower covers,

a substantially annular inlet formed in the annular body for ingress ofliquid into the cavity,

the annular body having a buoyancy sufficient for the liquid intake tofloat in a liquid with the annular inlet submerged below the surface ofthe liquid in which the liquid intake is floating,

a submersible pump within the cavity and having an inlet which in use issubmerged below the surface of the liquid in which the liquid intake isfloating,

the submersible pump having a discharge outlet in connection with a pipethat extends into the cavity, the pipe extending outside of the cavityfor connection to a liquid suction removal system.

A submersible pump has advantages in that it can pump to a greater headthan a suction pump. Moreover, the liquid intake of the invention can bemodified to include a submersible pump without difficulty, so that theapplication of the liquid intake of the invention can dictate whetherthe liquid intake operates under suction or with a submersible pump.

BRIEF DESCRIPTION OF DRAWINGS

In order that the invention may be more fully understood, someembodiments will now be described with reference to the figures inwhich:

FIG. 1 is a schematic illustration of a prior art pumping arrangement.

FIG. 2 is a schematic illustration of a pumping arrangement according tothe invention.

FIG. 3 is a side view of a floating liquid intake according to oneembodiment of the invention.

FIG. 4 is a plan top view of a floating liquid intake according to theinvention.

FIG. 5 is an exploded perspective view of the floating liquid intake ofFIG. 4 .

FIG. 6 is a cross-sectional view of the floating liquid intake of FIG. 4.

FIG. 7 is a part cut-away perspective view of the floating liquid intakeof FIG. 4 .

FIG. 8 is a side cross-sectional view through an annular body of thefloating liquid intake of FIGS. 4 to 7 .

FIG. 9 is a perspective view of the annular body of FIG. 8 .

FIG. 10 is as illustration of the floating liquid intake of FIGS. 4 to 7in use.

FIG. 11 is a cross-sectional view of an alternative floating liquidintake according to the invention, incorporating a submersible pump.

FIG. 12 is a part cut-away perspective view of the floating liquidintake of FIG. 11 with the submersible pump removed.

FIG. 13 illustrates a comparison with an existing tailings dam and atailings dam in which a liquid intake according to the present inventionis employed.

DETAILED DESCRIPTION

FIG. 2 is a similar illustration to FIG. 1 , but showing schematically,a floating liquid intake 20 according to the present invention in use.FIG. 2 illustrates several of the same features as FIG. 1 and for thosefeatures, the same reference numerals are applied. In FIG. 2 , it can beseen that the floating liquid intake 20 sits on the surface 21 of thebody of water 13 rather than being suspended within the body of water 13as shown in FIG. 1 . It will therefore be appreciated, that the inlet tothe liquid intake 20 is much higher than the inlet 16 of FIG. 1 . Thismeans that the inlet of the intake 20 of FIG. 2 is much further awayfrom the silt and debris 12 and is located in water which should becleaner than the water in which the inlet 16 of FIG. 1 is positioned.

FIG. 3 is a side view of a liquid intake 30 according to the presentinvention. The liquid intake 30 can be the same as the liquid intake 20of FIG. 2 . The liquid intake 30 has a housing 31 comprising an annularhollow and buoyant body 32, an upper dome shaped cover 33, a lower domeshaped cover 34 and a pipe 35. The annular body 32 includes an annularinlet 36 which includes screens 37 to resist or prevent debris frompassing through the inlet 36. The screens 37 are optional, although theyare particularly useful for screening large debris, such as fish,leaves, sticks and the like.

FIGS. 4 to 7 show different views of the intake 30 of FIG. 3 andreference will now be made to those figures. FIG. 4 is a plan view ofthe intake 30 and shows that the upper cover 33 includes a plurality ofstrengthening ribs 38 to extend radially from a central port closure 39.The closure 39 is provided for access to the interior of the intake 30and may be removed and replaced as required. The closure 39 is optionaland so alternative covers 33 will not include a closure 39. The closure39 is intended principally for intakes that include a submersible pumpas will be described later herein, as the ability to remove the closure39 provides ready access to the submersible pump. In manufacture, theclosure 39 can be formed integrally with the cover 33 and can be removedby cutting for example and re-attached by suitable fasteners.Alternatively it can be separately manufactured and suitable fastenerscan be employed to make the connection between the closure 39 and thesurrounding upper cover 33.

A second port closure 40 is provided and likewise provides access to thecavity within the intake 30 and likewise can be removed and replaced asrequired. The closure 40 is intended to provide access to within thecavity of the intake 30 adjacent to the inlet of the pipe 35 through thebody 32, so that the pipe 35 and associated components can be readilyaccessed.

FIG. 5 shows the intake 30 in exploded view and this view shows that theannular body 32 includes an opening 42 through which the pipe 35extends. The pipe 35 thus extends into the cavity 58 within the housing31, through the opening 42 of the body 32 and the pipe 35 extends to acoupling 43 and to a pipe intake 44. Alternatively, the pipe 35, thecoupling 43 and the pipe intake 44 can be formed integrally.

As shown in FIG. 6 , the intake 44 includes a downwardly facing intakeopening 45 which in use, is below the surface of the liquid within thecavity 58 when the intake 30 is submerged in a body of liquid. It is tobe noted however, that the downward facing orientation of the pipeopening 45 is not critical, and that it could alternatively openupwardly.

The annular body 32 is shown in cross-section in FIGS. 6, 7 and 8 , andin particular from FIGS. 6 and 8 , it can be seen that the body 32 isformed as a hollow body which is shown filled with a buoyant material46. This arrangement of filling the hollow annular body 32 with abuoyant material 46 is optional, but as explained earlier, the use of abuoyant material 46 can improve both the rigidity of the annular body 32and can prevent the intake 30 from sinking in the event of rupture ofthe wall of the annular body 32.

FIG. 9 shows the annular body 32 in isolation and that figure, it can beseen that the annular body 32 includes upper and lower surfaces 48 and49 and inner and outer edges 50 and 51. The inner edge 50 forms an innersurface of a lower ring 52 which is connected by webs 53 to an upperring 54. The opening 42 is formed in a tube 55 that extends through thelower and upper rings 52 and 54. The tube 55 is intended to be almostentirely submerged when the liquid intake 30 is operational as shown inFIG. 10 . The lower and upper rings 52 and 54 are separated by anannular inlet 36 which is interrupted only by the webs 53 and by theinlet tube 55. As shown in FIG. 8 , the outer diameter of the lower ring52 is less that the inner diameter of the upper ring 54. The annularinlet 36 forms the inlet for entry of liquid into the cavity 58 duringuse of the liquid intake 30 and can be overlaid by the screens 37illustrated in FIGS. 3, 5 and 7 , as required.

It will be evident from FIGS. 5, 6 and 7 , that the housing 31 forms theinternal cavity 58 between the upper and lower covers 33 and 34, and theannular body 32. Moreover, the pipe opening 45 of the pipe intake 44 ispositioned generally centrally of the cavity, or centrally of theannular body 32. That central positioning of the opening 45 means thatin a stationary body of water, water is entrained into the cavity 58from the same distance around the opening 45. FIG. 10 illustrates theliquid intake 30 in an in use condition, and the arrows A indicate thedirection in which water is entrained into the cavity 58 and it can beseen that the arrows extend completely about the circumference of theintake 30. Moreover, FIG. 10 shows the upper level of the body of waterwithin which the intake 30 is submerged and it can be seen from this,that the annular inlet 36 is completely submerged within the body ofwater. Assuming that there are no other air intake areas, so that theconnection between the upper cover 33 and the annular body 32 isgenerally airtight, and that the covers 39 and 40 of the upper cover 33are in place, then the only entrance into the cavity 58 is through thescreens 37 and the annular inlet 36. This tends to generate a vacuumwithin the cavity of the housing 31 which tends to raise the level ofliquid within the cavity 58 relative to the level of the body of waterwithin which the intake 30 is submerged. Depending on the volume beingpumped, substantially the entire cavity 58 can be filled with liquid.

As is explained earlier herein, by entraining water into the cavity 58through the annular inlet 36, the effect is that liquid enters the pipeintake 44 from the side, rather than from directly below (or directlyabove if the pipe opening 45 faces upwardly rather than downwardly). Asexplained earlier herein, the intake 30 can prevent the formation ofvortices by the direction of travel of liquid into the pipe intake 44,that being from the side rather than above or below, while the annularbody 32 itself disrupts the formation of vortices from outside theintake 30. Vortices are therefore prevented or minimised to the extentthat they do not cause any damage to the pumping station to which thepipe 35 extends, thus dealing with a major difficulty associated withprior art arrangements of the kind shown in FIG. 1 .

In addition, the position of the intake 30 at the surface of the body ofwater means that the water being entrained is the cleanest water in thatbody.

In order for the intake 30 to submerge in a body of water, it isnecessary for the air within the cavity 58 to be exhausted uponplacement of the intake on to the surface of the body of water. Air caninitially exhaust through the annular inlet 36, but water will sooncover the inlet 36 completely and so further exhaust through the inlet36 is not possible. The present invention thus employs an arrangement inwhich a column 61 is employed and the operation of that column isexplained later herein.

FIG. 7 also shows ribs or baffles 65 that have been included in thelower cover 34 and that extend upwardly from the cover 34 into thecavity 58. The baffles 65 are intended to resist movement of liquidwithin the cavity 58, in particular swirling movement, during operationof the liquid intake 30. That movement can generate air bubbles whichcan become entrained within the liquid entering the pipe intake 45 andso minimising the liquid movement is advantageous, noting that theremust be some movement within the cavity 58 for the liquid to be removedvia the liquid intake 30.

The intake 30 has been designed for use with a suction pumping system inwhich a suction pump or pumps are positioned remote from the intake onland, or on a floating body, such as a pontoon or barge, and areconnected to the intake 30 via an intake pipe 35, or another pipe orconduit connected to the intake pipe 35. The distance between thesuction pump or pumps and the liquid intake 30 can be in the order of 10to 30 meters.

Suction pumps have a limitation in that they have a theoretical maximumlift of no more than about 10 m. This assumes a perfect vacuum and veryfew friction losses and in practice, the suction lift is less than this.While that level of lift is suitable for many applications, if a greaterlift is required, than the present invention can employ a submersiblepump within the cavity 58 and this arrangement is illustrated in FIG. 11.

In FIG. 11 , the liquid intake 30 of the earlier figures has beenmodified to form the liquid intake 70 in which the pipe intake 44 isremoved and to include a submersible pump 75 which is positionedcentrally of the liquid intake 70 and beneath the closure 39. Thesubmersible pump 75 is of a known form and includes a discharge outlet76 that connects to a pipe 77. The pipe 77 is of a reduced diametercompared to the pipe 35 of the earlier figures and is supported withinthe opening 42 of the tube 55 by a pair of brackets 78 (see also FIG. 12in which the submersible pump 75 is not shown) that fill the opening 42and include an opening through which the pipe 77 extends.

The submersible pump 75 further includes a power cable 79 and a baseplate 80 to secure the pump 75 within the cavity 58. An inlet 81 sitsbelow the base plate 80 and liquid flows through the base plate 80, intothe inlet 81 for discharge through the outlet 76. A vacuum chamber pipe82 operates in the manner of the column 61 as hereinafter described toexhaust air from within the cavity 58 for pump priming purposes.

Returning to FIG. 6 , the liquid intake 30 is able to be primed via anopening 60 that extends through a wall of the pipe intake 44 and thatcommunicates with a vertical column 61 that extends into connection witha central opening 62 (see FIG. 5 ). The column 61 provides structuralrigidity to the pipe intake 44 by connecting the intake 44 with thecentre of the upper cover 33, but the column 61 also includes an openingin the region of reference numeral 63 and that opening 63 allows air toexhaust from within the cavity 58 as liquid enters the cavity 58,whereby the air passes into the column 61 through the opening atreference numeral 63, then downwardly through the column 61 and throughthe opening 60 into the intake 44. The air can then exhaust through thepipe 35. This process will continue until the level of liquid within thecavity 58 reaches the opening 60 in the intake pipe 44, so that nofurther exhaust of air through the column 61 can take place. However,upon generation of suction through the pipe 35, water rushing past theopening 60 will entrain air within the column 61 into the pipe 35, sothat a vacuum will be generated within the column 61. This will tend todraw air through the opening at reference numeral 63 and into the column61 and allow for the liquid level within the cavity 58 to rise. This iseffectively how the vacuum is generated within the housing 31 of theintake 30 as discussed earlier herein. The entrainment of air within thewithin the column 61 into the pipe 35 only occurs briefly and is notcontinuing. Accordingly, there is no detriment to the operation of theliquid removal system by this small volume of air that is pumped throughthe system.

Floating liquid intakes according to the present invention can beoperated from land or water borne vehicles or structures.

Floating liquid intakes according to the present invention can alsopermit significant reduction in the volume and surface area of ponds ordams, advantageously reducing losses through evaporation and reducingthe land required for ponds or dams to be installed. FIG. 13 illustratesa comparison with an existing tailings dam and a tailings dam in which aliquid intake according to the present invention is employed. For this,the required radius and resultant area of decant pond and exposedtailings beach area were determined for two scenarios:

-   -   a standard decant intake requiring a minimum 2 m pond depth, and    -   a liquid intake according to the present invention requiring        only 0.4 m minimum pond depth.

The comparison between the two scenarios is:

-   -   1. Standard intake, 2 m pond depth:        -   a. Required minimum pond radius around the decant intake:            133 m        -   b. Resultant decant pond surface area: ˜70,500 m²        -   c. Exposed beach area: ˜179,500 m² or 72% of total temporary            storage facility (TSF) area.    -   2. Invention intake, 0.4 m pond depth:        -   a. Required minimum pond radius around the decant station            intake: 27 m        -   b. Decant pond surface area: ˜2,300 m²        -   c. Exposed beach area: ˜247,700 m² or 99% of total TSF            (tailings dam) area.

For this conceptual scenario, the use of the Invention intake allows thepotential for

-   -   1. 96% reduction in the decant pond area, which also reduces        evaporative losses from the pond itself by 96%.    -   2. At an example daily mean evaporation rate of 10 mm per day,        this equates to a reduction in evaporative losses of 247        megalitres per year from the decant pond.    -   3. 38% increase in exposed tailings beach area, enhancing        tailings drying with potential improvement in deposited density        resulting in less frequent embankment raises and lower        associated costs.

The benefits of the Invention intake:

Decant Barge, Decant Tower etc Invention intake Minimum pond radius 133m 27 m Decant pond surface area ~70,500 m² ~2,300 m² Reduction in pondsurface area 0% 96% Exposed beach area ~179,500 m² ~247,700 m² Exposedbeach percentage 72% of total TSF area 99% of total TSF area Increase inexposed beach area 0% 38% Yearly evaporation saving 0 megaliters pa 247megaliters pa

This illustrates the potential magnitude of the benefit delivered by theInvention intake to an operation from environmental, reputational, riskmanagement and economic perspectives. Similar benefits would also beevident in deployment of the Invention intake into other TSFconfigurations.

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described. It is understood that the invention includes allsuch variations and modifications which fall within the spirit and scopeof the present invention.

Where the terms “comprise”, “comprises”, “comprised” or “comprising” areused in this specification (including the claims) they are to beinterpreted as specifying the presence of the stated features, integers,steps or components, but not precluding the presence of one or moreother features, integers, steps or components, or group thereto.

The invention claimed is:
 1. A floating liquid intake for a liquidsuction removal system, the liquid intake comprising a housing definingan internal cavity, the housing having: a buoyant annular body, an uppercover extending upwardly from the annular body, and a lower coverextending downwardly from the annular body, the internal cavity beingformed between the upper and lower covers, a substantially annular inletformed in the annular body for ingress of liquid into the cavity, a pipeextending into the cavity, the pipe including an inlet that in use isopen below the surface of the liquid within the cavity, the pipeextending outside of the cavity for connection to a liquid suctionremoval system, wherein the annular body has a buoyancy sufficient forthe liquid intake to float in a liquid with the annular inlet submergedbelow the surface of the liquid in which the liquid intake is floating,so that liquid entry into the cavity is by suction through the annularinlet from below the surface of the liquid.
 2. A floating liquid intakeaccording to claim 1, the annular body being a rotational moulded body.3. A floating liquid intake according to claim 1, the annular body beinga hollow body that is optionally filled with a buoyant material.
 4. Afloating liquid intake according to claim 3, the buoyant material beingpolyurethane (PU) foam.
 5. A floating liquid intake according to claim1, the annular body having upper and lower surfaces and radially spacedinner and outer edges.
 6. A floating liquid intake according to claim 5,the upper cover being attached to the upper surface and the lower coverbeing attached to the lower surface.
 7. A floating liquid intakeaccording to claim 5, the annular body having an opening through whichthe pipe extends and the opening extending through the annular body fromthe outer edge to the inner edge.
 8. A floating liquid intake accordingto claim 1, the annular body having an opening through which the pipeextends.
 9. A floating liquid intake according to claim 1, the liquidintake being generally airtight when submerged to a level at which theannular inlet is below the surface of the liquid in which the liquidintake is floating.
 10. A floating liquid intake according to claim 1,including debris screens overlying the annular inlet.
 11. A floatingliquid intake according to claim 1, the upper cover including a centralclosure for access to within the housing when removed.
 12. A floatingliquid intake according to claim 1, further including a submersible pumpwithin the cavity.
 13. A floating liquid intake according to claim 1,the lower cover including radial baffles projecting upwardly into thecavity.
 14. A method of using a floating liquid intake according toclaim 1, the method comprising connecting a liquid suction removalsystem to the pipe of the liquid intake and drawing water into thecavity of the liquid intake to generate a vacuum within the cavity, thevacuum tending to raise the level of liquid within the cavity relativeto the level of the surface of the liquid in which the liquid intake isfloating.
 15. A method of using a floating liquid intake according toclaim 14, wherein the level of water drawn into the cavity is such as tosubstantially fill the cavity with liquid.
 16. A floating liquid intakeaccording to claim 1, the intake being operable in water depths asshallow as 400 mm.
 17. A floating liquid intake according to claim 1,the annular inlet being formed in the annular body adjacent to the lowercover.
 18. A floating liquid intake according to claim 1, wherein thepipe has a diameter smaller than a diameter of the annular inlet.
 19. Afloating liquid intake for a liquid suction removal system, the liquidintake comprising housing defining an internal cavity, the housinghaving: a hollow and buoyant annular body, an upper cover extendingupwardly from the annular body, and a lower cover extending downwardlyfrom the annular body, the internal cavity being formed between theupper and lower covers, a substantially annular inlet formed in theannular body for ingress of liquid into the cavity, a submersible pumpwithin the cavity and having an inlet which in use is submerged belowthe surface of the liquid in which the liquid intake is floating, thesubmersible pump having a discharge outlet in connection with a pipethat extends into the cavity, the pipe extending outside of the cavityfor connection to a liquid suction removal system, wherein the annularbody has a buoyancy sufficient for the liquid intake to float in aliquid with the annular inlet submerged below the surface of the liquidin which the liquid intake is floating, so that liquid entry into thecavity is by suction through the annular inlet from below the surface ofthe liquid.
 20. A floating liquid intake according to claim 19, whereinthe pipe has a diameter smaller than a diameter of the annular inlet.